From: Nigel Taylor (nigel_taylor@xxxxxxxxxxx)
Date: Wed Aug 15 2001 - 22:09:54 GMT-3
Xuan,
I don't have a copy of the Vol II but a couple of things stand
out in your scenario...
First, you mentioned the idea is to use the community "no-export" to control
the advertisements
of internal routes to AS300, however you would like AS300 to see the
aggregate address and
not any of the specific routes. Well the use of the aggregate address <ip
addr summary> summary-only
will take care of you second requirement but the community string no-export
says do not advertise
to a specific peer or group of peers(peer groups). The community string is
not lost.. the community
is sent/applied with the use of the command "nei <nei ip address> send
community, once applied the AS
will carry this community within the existing routing domain until it is
passed to another AS.
HTH
Nigel..
----- Original Message -----
From: <Xuan.Sun@Seagate.com>
To: <ccielab@groupstudy.com>
Sent: Wednesday, August 15, 2001 7:08 PM
Subject: Doyle, Routing TCP/IP Vol II. PP 189: Community attribute is lost
under IBGP
> I have set up the network based on Fig 3-11. Please refer to the Routing
> TCP/IP Volume II, Page 189. I can not draw it here.
>
> The idea is to use NO-EXPORT to control the internal network address to
> leak to AS 300. So the router under AS 300 only see the aggregate address,
> not the specific-route. But this solution is not worked in one condition.
>
> If the link between Diamond and Burke broken and the link between Stowe
and
> Sugarbush broken, you will see all the specific routes in Burke router.
The
> reason is the community attribute of NO-EXPORT is lost when it distributes
> in the IBGP peer. Under Example 3-55 in Page. 293, it has showed two BGP
> entries for 192.168.199.0. One is from EBGP peer, obviously has NO-EXPORT
> attribute. One is from IBGP peer, no NO-EXPORT.
>
> Am I rigtht ?
> **Please read:http://www.groupstudy.com/list/posting.html
**Please read:http://www.groupstudy.com/list/posting.html
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